It might be common wisdom that you need to iterate your design. During the development of the Draftsman multi-tool, as soon as a model had been finished in CAD it was 3D printed. This gives you something tangible within the hour that you can play around with and get the "feel" of it. In a perfect world, you would design your widget and account for everything and make it, and it would be glorious. However, the problem is that people might end up having to use your widget, and